5 reasons why the engine can suddenly "clatter fingers"

Many have noticed that when the engine is running, a soft metallic sound is suddenly heard, which experienced drivers instantly recognize as “knocking fingers”. And there are situations when the ringing almost drowns out the operation of the motor. What such a soundtrack can talk about, the AvtoVzglyad portal tells.

Let's start with a little theory. The piston pin, which is the cause of the ringing, is a metal axis inside the piston head to secure the connecting rod. Such a kind of hinge allows you to create a movable connection, which is transferred to the entire load during the operation of the cylinder. The solution itself is reliable, but it also fails.

Most often this happens when engine parts are badly worn out. Or a variant is possible when a knock appears after a handicraft repair. For example, the craftsmen chose the wrong size parts and because of this, the fingers do not match the seat. As a result, backlashes are obtained, vibrations increase, extraneous sounds go. If you do not pay attention to this, then new parts will also have heavy wear, which will have to be changed again.

Experienced craftsmen determine the sound of fingers by ear. If the motor is worn out, then special devices are not needed for this, but if the problem has just appeared, they use a stethoscope, applying it to the walls of the cylinder block. By the way, even a medical one is suitable, because they listen to the unit by analogy, as with a sick patient.

Another common reason lies in the detonation of the engine due to poor quality fuel or even “singed” gasoline. With such fuel, a premature explosion of the air-fuel mixture occurs, which prevents the piston from running correctly. As a result, the piston skirts against the walls of the sleeve. This is where the metallic ringing comes from, especially during acceleration. If you start the problem, then scuffs appear on the walls of the cylinders, which brings the engine closer to a major overhaul.

Remember that detonation does not occur in one cylinder, but in several at once. Therefore, its consequences will be reflected in the entire motor.

Finally, metallic knocking can occur if the engine is clogged with deposits. Because of this, the piston head is displaced and warped, and its skirt hits the cylinder wall. This is accompanied by strong vibrations, as if the motor is shaking by an unknown force.